Method of turning and threading bolt-blanks.



c. K. LASSITER. METHOD OF TURNING AND THREADING BOLT BLANKS. APPLICATIONFILED NOV. 22, 1910.

1,007,578.- Patented 0011311911.

4 SHEETS-SHEET 1.

544mm Calzzmba-szKLasszlier C. K. LASSITER.

METHOD OF TURNING AND THREADING BOLT BLANKS.

Patented Oct. 31, 191 1.

4 SHEETSSHEET 2.

APPLICATION FILED NOV. 22, 1910.

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METHOD OF TURNING AND THREADING BOLT BLANKS.

APPLICATION FILED NOV. 22, 1910.

Patented Oct. 31, 1911.

4 SHEETSSHEET 3.

Fig.6.

wmmw G. K. LASSITER.

METHOD OF TURNING AND THREADING BOLT BLANKS.

PatentedOct. 31, 1911.

4 SHEETS-SHEET 4.

APPLICATION FILED NOV. 22, 1910.

awe/MM CalumhzaKLaasifer COLUMBIA PLANOGRAPH (IO-.WASHINGTON D c UNITEDSTATES PATENT OFFICE.

COLUMBUS K. LASSITER, OF RICHMOND, VIRGINIA.

METHOD OF TURNING AND THR-EADING BOLT-BLANKS.

To all whom it may concern:

Be it known that I, CoLUMBUs K. LASSI- TER, a citizen of the UnitedStates, residing at Richmond, in the county of Henrico and State ofVirginia, have invented new and useful Improvements in Methods ofTurning and Threading Bolt-Blanks, of which the following is aspecification.

This invention relates to a method of turning and threading bolt-blanks.

Heretofore completed bolts have been formed from blanks in the rough byfirst turning or finishing the blanks and then threading the same, amethod requiring two separate and distinct operations.

The object of my invention is to provide a method whereby the steps ofturning and threading may be simultaneously performed, thus enablingcompleted bolts to be produced from the blanks in a single continuousoperation, with resultant reduction in time and labor and economy ofmanufacture.

In the accompanying drawings I have shown certain mechanical means forcarrying my method into practical effect, without, however, intending tolimit the inven-' tion to the particular type of means which, for sakeof illustration, I have set forth.

In the said drawings :Figure 1 is a front elevation of a bolt turningand threading device embodying my invention. Fig. 2 is a centralvertical section through the supporting parts and turning cutterthereof, showing the threading cutter in elevation. Fig. 3 is asectional elevation of the threading cutter and the die controllingdevices associated therewith. Fig. 4: is a detail section on line 44 ofFig. 2, showing the construction of one of the stop or gage collars.Fig. 5 is a vertical transverse section of the same. Fig. 6 is a topplan view, partially in section, of the threading cutter, showing indotted lines the movements of certain parts. Fig. 7 is a sectional viewon the line 77 of Fig. 6. Fig. 8 is a detail section on the line 8-8 ofFig. 3, showing the trip lever in retracted position and also showingthe means for locking and releasing the cam ring whereby the threadingdies are adjusted.

Fig. 9 is a detail view of the upperend of the locking pin. Figs. 10 and11 are detail views of one of the keepers or looking blocks. Fig. 12 isa top plan view of the main sup-- porting ring. Fig. 13 is a perspectiveview of one of the leveling sleeves. Fig. 1 1 is a similar view of oneof the retaining pins or Specification of Letters Patent.

Application filed November 22, 1910.

Patented Oct. 31, 1911. Serial No. 593,651.

structure and is provided at one side with a I guide ear 3 and aninternal keyway or groove 4: extending from the base of said ringupwardly to and intersecting an annular seat groove 5 formed in the topthereof.

Removably mounted in the upper portion of the frame ring or support 1 isa turning cutter head comprising an annular body portion 6 and a bottomplate 7, said body portion being provided with a laterally extendingannular flange 8 to seat within the groove 5 and thereby support saidhead in position. The body portion 6 is closed at its base by the bottomplate 7 to which it is detachably secured by screws 9, both the bodyportion and bottom plate being provided with alining keys 10 to engagethe keyway 4, whereby the turning head will be held from rotation in theframe ring and may be seated accurately therein in proper working.position.

Arranged within the body portion 6 and supported by the plate 7 is aseries of turning cutters 1-1, spaced at their inner or cutting ends andadjustable radially by means cutting ends or edges of said cutters maybe 1 relatively disposed to provide an intervening passage of propersize for the downward feed of a bolt-blank of any diameter and to turnor finish the surface of the bolt on its feeding movement. Each cutter11 is prog vided in one of its sides with a longitudinal groove 14receiving the head of a screw 15 carried by the plate 7, the said headof the screw being arranged to bear against the bottom wall of thegroove so that a desired friction may be instituted to prevent too freeradial movement of the cutter, the screw also acting to hold the cutteragainst vertical displacement. The acting ends of the turning cuttersare arranged above an opening or which the bolt-blank is fed.

The lower portion of the frame ring 6 receives the upper portion of theguide frame of a threading cutter, which guide frame comprises a ring 17arranged to bear against the under side of the plate 7 and detachablyheld in position upon said frame ring by turn buttons 18 integral withturn screws 19 carried by the frame ring, which buttons bear against theunder side of the ring 17 and may be swung outwardly to permitthe sameto be withdrawn from the frame ring. The ring 17 is suitably fixed toand connects the upper ends of an annular series of guide rods 20,preferably four in number, arranged at equal distances apart and coupledat their lower ends by nuts 21 to a lower ring or supporting member 22having an opening 23 for the downward passage of the completed boltthere through. The ring 17 is provided with a key 24: to enter the lowerend of the keyway 4, whereby it may be inserted with precision in theframe ring 1 and held from rotary movement.

The guide frame carries a'threading cutter arranged for operation belowthe turning cutter and comprising a head formed with an annular baseportion 25 and a re duced annular upstanding portion 26, said head beingprovided with a central vertical passage arranged in alinement with thepassage 16 for the downward feed of the boltblank therethrough. Theportion 27 is formed with radial guideways 28 in which are slidablymounted adjustable blocks 29 carrying a series of threading dies orchasers 30. The outer ends of the blocks are provided with cam surfacesengaged by cam surfaces 31 on a cam ring 32 surrounding the portion 26,by which the threading dies may be adjusted radially inward to act upondifferent diameters of bolts the blocks being in practice movedoutwardly by individual springs 33 to retract the dies. The cam ring isnormally maintained in die-retracting position by one or more springs 84seated in grooves 35 therein, each spring hearing at one end against ashoulder 86 on the portion 26 and at its opposite end against anabutment screw 37 on the cam ring. WVhen the cam ring is returned tonormal position by the springs 34, after having been turned to projectthe dies, the cam surfaces 31 move out of contact with the blocks 29 andallow the springs 38 to retract the dies, thus freeing the threaded boltfor discharge.

The cam ring is provided atone side with a radial stud 38 adapted to beengaged by the actuating arm 39 of a die closing lever 10 provided witha stem 41 ournaled in the ear or projection 3 of the frame ring 1, themovement of the stud from die opening to die closing position beingindicated in dotted and full lines in Fig. 6. The cam ring is adapted tobe automatically locked when adjusted to die closing position, to bemaintained in such position until the surface of the bolt-blank isthreaded, and then to be automatically released for the retraction ofthe threading dies, as hereinafter fully described. The threading cutterhead is mounted to have a floating or vertically yielding compensatingmovement on the guide rods 20, and to this end the base 25 thereof isformed with openings 42 for the passage of the rods, each of whichopenings is formed in one side with a segmental notch or seat 13. Whenthe threading head is in normal position, the upper end of the cam ringenters the opening 414 of the ring 17 and is thus centered in positionto accurately dispose the dies 30 to receive and grip the lower end ofthe bolt-blank as it passes be low the turning cutters.

As shown, the openings 1-2 are of greater diameter than the rod, and areset eccentrically with relation to guiding and leveling sleeves 45encompassing the rods below the head and fixed at their lower ends to asupporting ring 46 having openings for the passage of the rod and anopening 17 for the downward feed of the bolt. Surrounding the sleevesare coiled balancing or compensating springs 48 which bear against theunder side of the base 25 of the threading cutter head and normallysupport said out ter head in the receiving position stated and permit avertical yielding movement thereof under certain conditions in thethreading operation hereinafter explained. When the cutter head isdisposed in its normal receiving position it is held a short distanceelevated above the sleeves 45 by the springs 48, but is permitted tohave a limited prelimi nary downward movement until it contacts with thesleeves, as indicated in dotted lines in Fig. 2. By a limitedoscillatory movement the head will be turned to bring the openings 12into coaxial alinement with the sleeves, thus allowing the same totravel to a greater extent downward upon the sleeves against theresistance of the springs 48.

The oscillatory movement of the cutter head is controlled and regulated.by sliding plungers 5L9 movable in openings 50 in the base 25 andprovided at their inner ends with vertically disposed segmental presserfeet or lugs 51 arranged within the openings 12 and bearing upon therods. The bores 50 are closed at their outer ends by screw plugs 52 andeach plunger is hollow to receiveacoiled expansion spring 53 by which itis forced inwardly to cause the presser foot to bear upon the rod, thepressure of the several springs 53 serving to normally hold the portions13 of the head in engagement with the rods and the openings 42 out ofaxial alinement with the sleeves 415, so that on the preliminarydownward movement of the head the latter will engage the sleeves andwill be held thereby against further downward move-- ment until the headis turned against the resistance of the springs 53 to dispose theopenings 42 in axial alinement with the sleeves. The presser feet 51 areof sufficient length to project below the cutter head and enter and movevertically in guide slots 54 in the leveling sleeves, thus preventingthe head from being turned or oscillated too far in either direction andmaintaining at all times a guiding connection between the sleeves andhead in the vertical movements of the latter. The tension of the springs53 may be regulated by adjusting the plugs 52.

Fixed to the underside of the base 25 is a depending bracket 55 having ahorizontal arm 56 slidably supporting the lower reduced end 57 of alocking pin 58. This locking pin is slidably and rotatably mounted in abearing opening 59 extending through the base 25 and is transversely cutaway at its upper end to provide a locking finger or shoulder 60. Thisfinger 60 enters a circumferential slot 61 formed in the cam ring 31, inwhich slot is arranged a locking block or keeper 62 having an endlocking shoulder 63 and cut away on its under side to form a diagonallyarranged inclined or cam surface 64. WVhen the cam is turned to projectthe dies 30, the shoulder 63 of the block engages the finger 60 of thelocking bolt 58, by which the cam is held from retrograde movement andthe die is held projected for the thread ing operation. The block 62 iscarried by a screw 65 movable in a slot 66 in the outer wall of the slot61 and passing through a clamping plate or washer 67, by which the blockmay be adjusted in the slot to vary the throw of the cam ring and thelocking action, so that the normal position of the dies 40 may bechanged to over or under thread boltblanks of a given size, or, in otherwords, to vary the depth of the threads as occasion may require. A screw68 is provided upon the cam ring to gage and limit the extent ofadjustment of the locking block. The looking pin is also provided with alateral looking lug 69 to engage a flange or recess 7 O at the lower endof a locking block or keeper 71 secured upon the under side of the base25, to hold the pin from oscillatory movement while its finger 60 is inengagement with the shoulder 63.

A trip lever 72 is intermediately fulcrumed upon the lower end of thelocking pin, as at 73, for pivotal movement in a vertical plane and hasone of its arms extending outwardly and provided with a rounded lug 74for rocking engagement with the under side of the base 25 and its otherarm extending inwardly and formed with an internally threaded sleeve 75receiving the lower threaded end 76 of a contact pin 77, which pinprojects upwardly into the opening 27 so as to be engaged by the lowerend of the feeding bolt-blank 78. A coiled spring 79 surrounds theportion 57 of the locking pin between the body portion of said pin andthe bracket arm 56 and normally serves to force said pin upwardly. Asecond coiled spring 80, of the torsion type, surrounds the part 57 andis terminally connected with the same and an extension 81 from thebracket 55 and operates when the bolt is depressed and the cam turned todie projecting position to swing said bolt and the trip lever laterallyand thereby move the contact pin 77 into the path of movement of thebolt.

Milled stop and gage collars 83 are provided upon the rods 20 to supportand limit the downward movement of the ring 46, leveling sleeves 45 andthe threading cutter head, by which the floating movement of the cutterhead will be restricted within determined limits sufficient to effectthe threading of bolt-blanks of determined lengths. Each of thesecollars is formed at one side with a radial slot 84 receiving acorrespondingly movable locking block or member 85 secured to one end ofa substantially semicircular spring 86, fixed at its opposite end to thecollar, as at 87. The block or locking member 85 is adapted to engage atransverse notch 88 in the rod to hold the collar from vertical oroscillatory movement. By, however, gripping and turning the collar withsufiicient force, the inner end of the block will ride on the inner endof the slot as a cam surface and be forced outward or be retracted,permitting the collar to be released for adjustment. When so releasedthe collars may be moved downwardly and seated upon the upper securingnuts 21, allowing the threading cutter head to have a greater range ofvertical movement.

In the operation of the device, the boltblank 78 is fixed at its upperor headed end in a chuck or feed device having a downward feed motion ata desired rate of speed and also adapted to impart a rotary motion at adetermined rate of speed to the blank,

after which time the lever 40 is operated to turn the cam 31 in themanner described to project the threading dies into engagement with theblank. As the blank feeds downward it first passes between the turningcutters 11 and its outer surface is turned or finished by the actionthereof. The finished portion of the bolt passing below the turningcutters and through the opening 16 then enters the opening 27 in thethreading cutter head between the dies 30. In this operation themovement of the cam to its prescribed position causes the shoulder 63 ofthe locking block 62 to engage the finger 60 of the locking pin 58, bywhich the cam will be held from retraction to hold the dies projected.The engagement of the boltblank by the threading dies causes thethreading cutter to first move downwardly from its normal position underthe feeding fixed against movement.

movement of the blank to the dotted line position shown in Fig. 2, bywhich the cutter iead is brought into engagement with the upper ends ofthe sleeves and leveled to cause the dies to grip the blank accuratelyto form a perfect and true thread. As soon as the head engages theleveling sleeves as described, the threading dies securely grip the boltblank to start their threading aci tion and the dies and cutter head arepermitted to turn wit-h the blank to the extent limited by the openingsl-2 and until said openings are brought into coaxial alinement with thesleeves 45, thus providing a compensating and vertical downward movementfeeds.

It is preferred in practice to feed the blank at a fairly rapid speedthrough the machine in order to enable a comparatively large number ofblanks to be finished and turned within a determined period of time. Theturning cutters 11 will act efficiently upon the blanks at any rate ofspeed within reasonable limits, but it will, of course, be understoodthat the speed of action of the threading cutters on the blanks willvary according to the pitch of the threads to be formed, and that someprovision must be made to compensate for the differences in the rate ofturning and threading feeds I when a fine or coarse thread is to beformed.

If the thread is of such a pitch that the threading cutters will operateat the same ratio as the turning cutters or thread the blank as fast asit passes through the turnl ing cutters, it will. be understood that thethreading cutter head will simply have its preliminary downward movementand partial rotary movement for a leveling and gripping action and willthen remain sta' tionary on the guide rods 20. If, however, the threadpitch should be comparatively fine, in which event the threading feedwill be slower than the turning feed, the threading cutter will movedownward on the guide rods against the resistance of the springs d8 toallow the blank to have its usual rate of downward feed motion, whileincreasing the rate of travel of the threading cutter for the threadingaction, thus compensating for a variation in the turning and threadingspeeds when the former is faster than the latter. When, on the contrarythe thread to be formed is of coarse pitch, in which event the threadingcutters will operate as fast as the bolt is fed or at a higher rate ofspeed, it will be understood that the threading cutter will simply haveits preliminary downward rotary motions for a leveling and grippingaction and may then remain stationary or feed upwardly on the threads asit forms the same to compensate for the difference between the turningand threading speeds under such conditions. By this operation of makingthe threading cutter movable with relation to the turning cutter andinstituting a compensating feed action of the character described, boltblanks on which any desired pitch of thread is to be formed may besimultaneously turned and threaded in a single continuous operation anda comparatively large number of bolts finished within a determinedperiod. with much better results and at less cost than where the usualpractice of turning and threading the bolts by two separate andindependent operations is pursued.

As the blank 7 8 feeds downward through the opening 27 it contacts withthe pin 77 and gradually depresses said pin and tilts the arm 72 of thetrip lever downward. By this means the finger and lug 69 are graduallydrawn out of engagement with the shoulder 63 of the locking block 62 andthe flange 7 O of the locking block 71. The lever will be fullydepressed by the blank against the resistance of the spring 79 at theend of the threading operation, so that said finger and lug will befully retracted, thus freeing the cam ring 31 for return movement by thesprings 34 to retract the threading dies and at the same time freeingthe locking pin for rotary motion, so that under the pressure of thebolt on the pin 77 and through the action of the cam surface 64: of theblock 62 on the finger 60 as the cam turns the trip lever will be turnedlaterally to swing the pin 77 out of the path of the bolt and into thereceiving recess 82, allowing the bolt to pass downward through theopenings 27, 4:7 and 23 without interference. When the bolt is incontact with the pin 77 on its downward feed, it will be understood thatits tendency is to swing the pin laterally in the reverse direction,which operation would cause, if

permitted, an oscillatory motion of the pin 58, by which the cam ringwould be allowed to turn a slight distance back and forth and adjust thecutters to form an irregular or imperfect thread. To prevent thislateral motion of the pin 58, the locking devices 69 and 70 areprovided, as will be readily understood. As soon as a new bolt isinserted in position and the cam ring turned to pro ject the dies, itwill be understood that the cam surface 64 will move out of engagementwith the finger 60, and by the movement of the ring the shoulder 63 ofthe block 62 will clear the finger 60, whereupon the pin 58 will be freeto be forced upward and turned by the springs 7 9 and 80 to adjust saidfinger into locking engagement with the shoulder 63 and swing the pin 77 into position to be engaged by the succeeding bolt, thus automaticallyresetting the trip mechanism for further operation.

It is desirable to provide means whereby the end of the blank to bethreaded may be reduced in diameter prior to the threading action, inorder to allow the turned body of the blank to be subsequently turneddown to a taper on a separate machine for the production of a taperedbolt. To this end I provide upon the portion 26 of the threading cutterhead one or more turning cutters arranged between adjacent threadingdies. In the present instance I have shown a single reduction cutter,although a plurality may be used, said cutter comprising a support 89having front and rear guide pieces 90 and 91 perforated to form supportsfor a sliding turning tool 92, to which tool is fixed a stop collar 93which limits its inward movement and a laterally projecting arm 94. Thearm .94: carries a pin 95 movable in a guide opening in the guide piece91, and a coiled spring 96 surrounds the cutter between the guide piece90 and the collar 93 and serves to hold the cutter normally retracted.The stem 95 is adapted to be engaged by a cam member 97 carried by abracket piece 98 secured to the upper face of the cam ring 32, wherebythe reducing cutter will be projected when said cam ring is turned toproject the threading dies. It will thus be seen that upon the downwardpassage of the blank beyond the turning cutters 11 the lower end of theblank will first be reduced to the desired extent by the reducing cutter92 and the reduced portion threaded by the threading dies. The bolt thusproduced will, therefore, have a threaded end of less diameter than thebody thereof, allowing the body to be turned down to a desired taper bytaper cutters on a separate machine.

I claim 1. The herein-described method of turning and threadingbolt-blanks, which consists in feeding the blank at a determined speed,turning the feeding blank, and threading the turned portion of the blankwhile the turning action is still in progress at a feed ratiocorresponding to any variation between the feed ratio for the turningcut and that due to the pitch of the thread to be cut.

2. The herein described method of turning and threading bolt blanks,which consists in feeding the blank along a determined path of travel ata determined speed, turning the blank at a point in its path of feed,threading the turned surface of the blank at a point in its path of feedbeyond such turning point while the turning action is in progress, andvarying the threading and turning points with relation to each other tocompensate for any variation between the rate of advance or feed for theturning out and that due to the pitch of the thread to be cut.

3. The herein described method of turning and threading bolt blanks,which consists in rotating and feeding the blank at a determined speed,simultaneously turning and threading the blank, and varying thethreading point with relation to the turning point to compensate for anyvariation between the rate of advance or feed for the turning cut andthat due to the pitch of the thread to be cut.

4. The hereindescribed method of turning and threading bolt blanks,which consists in rotating and feeding the blank at a determined speed,turning the blank at a fixed point in its path of feed, threading theturned surface of the blank while the turning action is in progress, andmoving the threading means with relation to said fixed turning point tocompensate for any variation between the rate of advance or feed for theturning out and that due to the pitch of the thread to be cut.

5. The herein described method of turning and threading bolt blanks,which consists in turning a feeding blank, threading the turned surfaceof the blank while the turning action is in progress, and varying thepositions of the turning and threading points with relation to eachother to compensate for any variation between the rate of advance orfeed for the turning out and that due to the pitch of the thread to becut.

6. The herein-described process of turning and threading bolt-blanks,which consists in.

establishing a relative feed motion between a blank and turning andthreading devices, turning the bolt by means of the threading device,threading the turned portion of the bolt by means of the threadingdevice while the turning action is still in progress, and varying thepositions of the turning and threading devices with relation to eachother to compensate for any variation between the rate of advance orfeed for the turning out and that due to the pitch of the thread to beout.

In testimony whereof I afiix my signature in presence of two witnesses.

COLUMBUS K. LASSITER.

C. C. Hnvns.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

' Washington, D. G.

